Wearable Potentiometric Sensor Based on Na 0.44 MnO 2 for Non-invasive Monitoring of Sodium Ions in Sweat.

Here, we present a wearable potentiometric ion sensor for real-time monitoring of sodium ions (Na + ) in human sweat samples using Na 0.44 MnO 2 as the sensing material. Na 0.44 MnO 2 is an attractive material for developing wearable electrochemical sensors due to its good Na + incorporation ability, electrical conductivity, stability, and low fabrication cost. In the first step, the analytical performance of the electrode prepared using Na 0.44 MnO 2 is presented. Then, a miniaturized potentiometric cell integrated into a wearable substrate is developed, which reveals a Nernstian response (58 mV dec -1 ). We achieved the detection of Na + in the linear ranges of 0.21-24.54 mmol L -1 , which is well within the physiological range of Na + . Finally, for on-body sweat analysis, the potentiometric sensor is fully integrated into a headband textile. This platform can be employed for non-invasive analysis of Na + in human sweat for healthcare and disease diagnosis.